Irradiating articles with ionising radiation makes it possible to load them with a particular radiation dose, including internally. In this context, depending on the radiation used and the purpose, there is more or less spatially unresolved radiation (that is to say, the body is loaded with a substantially equal radiation dose substantially over the whole volume region thereof), surface-resolved radiation (that is to say, there is structured loading as a function of the x and y coordinates in a plane, but no structured radiation in terms of depth or in the z direction) or else even three-dimensionally structured radiation (that is to say, radiation with spatial resolution in all three spatial directions).
Radiations in the medical field are one example application among many radiations of this type. In the meantime, the spectrum for a use of ionising radiation in medicine varies over a wide range. For example, X-rays in which a patient is loaded with substantially unstructured radiation have been established as a diagnosis method for many years. Depending on the type of tissue which is irradiated (for example soft tissue, bone, air cavities and the like), the X-ray radiation is weakened by varying amounts, and the X-ray film located behind the patient is thus blackened by different amounts. An example application of three-dimensionally structured radiation is the treatment of tumours with particle radiation. Photons and electrons are sometimes used for this purpose. In recent years, however, the treatment of tumours using heavy ion radiation has also been developed considerably, since heavy ion radiation, because of the distinctive Bragg peak thereof, provides an excellent opportunity to implement precise structuring in terms of depth (in the z-direction; parallel to the particle beam), in the millimeter range.
In particular in cancer treatment, it is necessary to introduce a particular, comparatively high, cell-damaging dose into a volume region located inside the body (namely at the location of the tumour to be treated), whereas the remaining tissue of the patient should experience as weak a radiation dose as possible. This is the case in particular for critical tissue regions (often designated as OAR, “organ at risk”), in which particular (generally relatively low) maximum radiation doses must not be exceeded under any circumstances. Critical tissue regions of this type are for example nerve tissue, blood vessels, particular internal organs and the like.
So as to be able to introduce three-dimensionally structured radiation of this type, the radiation process has to be adjusted suitably (for example in terms of beam guidance, particle energy and the like). Since in the meantime what are known as scanning methods have become established, in which a pencil-thin particle beam (known as a “pencil beam”) departs from rows, columns and layers of the tissue to be treated in succession, a set of parameters which are to be applied in temporal succession may also be required for controlling the radiation device (in a manner varying over time). In practice, comprehensive calculations are required for this purpose, particular assumptions and empirical values (which are not necessarily exactly correct) also contributing to the calculations. So as to be certain that the obtained parameters are correct, what are known as radiation phantoms have already been in use for some time. For checking purposes, they are loaded with the radiation, instead of the patient. Only when the radiation result is satisfactory is the obtained radiation plan actually introduced to the patient.
Particular requirements—both in terms of the radiation phantom and in terms of the requirements on the calculation of a radiation plan—come up when movements also have to be taken into account. This is the case for example if the tumour moves perceptibly during the treatment. This is the case for example if the tumour is located in or adjacent to the lung, in or adjacent to the heart or on or adjacent to the intestine.
In the meantime, a wide range of methods have been proposed so as to be able to obtain a radiation plan even with constraints of this type. A summary is found for example in the publication “Special report: workshop on 4D-treatment planning in actively scanned particle therapy—recommendation, technical challenges, and future research directions”, by A. Knopf, C. Bert, E. Heath, S. Nill, K. Kraus, D. Richter, E. Hug, E. Pedroni, S. Safai, F. Albertini, S. Zenklusen, D. Boye, M. Söhn, N. Soukup, B. Sobotta and A. Lomax in Med. Phys. 37 (9), September 2010, pages 4,608-4,614.
Although the above-disclosed calculation methods and radiation devices are very promising, the problem still remains of checking the quality thereof in advance, before an animal or a human is loaded with the planned dose in accordance with the radiation plan.
There are thus a wide range of radiation phantoms to date, but they are often not movable, in particular not internally movable. In cases where movements can be simulated, the metal components which are conventionally used in this case are found to be problematic, since they make either the actual radiation process or else at least the measurement processes difficult, or even impossible, and the data thus obtained can be worsened to the point of becoming unusable. Moreover, the movements which can be represented in radiation phantoms known thus far are often found to be insufficient. For example, in many known radiation phantoms merely 1D movement can be represented.